Ring shaped spring device

ABSTRACT

A spring device comprising at least one annular support plate defining a ring with a central axis; a plurality of circumferentially spaced, parallel oriented coil springs disposed about the at least one annular plate; and, a plurality of lock assemblies spaced about the plate. Each of the lock assemblies being in position within a spring cavity of one of the coil springs to allow additional springs to be provided on the spring device. In addition, the lock assemblies are dimensioned so that the coil spring is retained in a prestressed condition.

The present invention relates to a spring device and more particularlyto a spring device of the type used in automatic transmissions for motorvehicles.

INCORPORATION BY REFERENCE

Automatic transmissions for vehicles often include a plurality of coilsprings that are adapted to apply a biasing force against clutch platesthat control the engagement of various gears in the transmission. Thesecoil springs are assembled in a ring shaped device comprising twoannular plates having a multiplicity of circumferentially spaced,parallel compression coil springs mounted therebetween. Such a ringshaped spring device is disclosed in Orlowski U.S. Pat, No. 5,306,086,which is incorporated by reference herein as the basic background towhich the present invention is directed. A ring shaped spring device isalso disclosed in pending application Ser. No. 10/078,465 filed on Feb.2, 2002 which is incorporated by reference herein as the basicbackground to which the present invention is directed.

BACKGROUND OF INVENTION

In the ring shaped spring device disclosed in Orlowski, there is a pairof spaced apart first and second annular support plates defining thering shape of the spring device. A plurality of circumferentially spacedparallely oriented coil springs are disposed between the annular platesso that vertical movement of one plate toward the other compresses thesprings. To interconnect the plates, an integral hook is formed in oneplate and a loop is integrally formed in the other plate. The hook andloop are designed so that the device can be assembled by merely locatingthe various coil springs and then pressing one plate toward the other.The hook snaps over the loop to lock the plates together, with the coilsprings partially compressed. However, when assembled in a transmission,the ring shaped spring device is compressed further so that the hookactually disengages the loop. Consequently, during repetitive operationof the spring assembly over many years, the individual coil springs canbecome canted in a manner to reduce the spring constant and cause damageand/or unintended biasing forces. By compressing the spring device forshifting the gears of the automatic transmission, distortion of the coilsprings in the annular direction is magnified. Consequently, the priorring shaped spring device, as shown in Orlowski only employs the conceptof integral interconnecting elements and does not address the problem ofcontrolling the annular movement of the spaced plates during long termoperation of the spring device. Orlowski also must remove four of hiscoil springs to provide space for integral hooks used to maintain theplates relative to one another. As a result, the force produced by theOrlowski spring device is not maximized and is not balanced. The springassembly in copending application Ser. No. 10/078,465 is a differentmechanism to overcome the deficiency of Orlowski regardingcircumferential shifting. But, this design uses spaces which shouldaccept coil springs.

THE INVENTION

The present invention relates to a ring-shaped spring device as shown inOrlowski wherein there are a plurality of locking assemblies located atcircumferentially spaced positions around the ring that are each withinone of the coil spring's center passage. In this respect each of theselock assemblies includes a first element extending from one of theplates toward the other plate, a second element extending in theopposite direction from the other plate to form a generally slidingcontact between the first and second elements as the spaced plates movevertically to compress and release the coil springs. The first andsecond elements are sized and shaped to fit within the center passage ofthe coil spring. This configuration maximizes the force produced by thering shaped spring device and balances the circumferentially extendingspring action.

In accordance with another aspect of the present invention, the firstand second elements or tabs include a guiding mechanism to restrictannular movement at the plates relative to one another. The first tabhaving a guide slot with a given width and which extends in a directionperpendicular to the plates. The second tab having a hook shaped guidemember which extends through the guide slot to restrict the verticalmovement between the two plates. The width of the hook corresponds withthe width of the slot which provides the guiding mechanism between thetwo plates. The structure assembly procedure and operation of thepresent invention is different than the ring shaped spring device inOrlowski. These added features further result in the advantage of beingcapable of maintaining the proper annular orientation between the spacedplates during long term operation of the spring device in an automatictransmission.

Still another aspect of the present invention, the guide slot has an endremote from the plate from which the second tab extends. The distance ofthis end from the plate maintains the coil springs in a compressed orprestressed condition when the device is assembled.

Yet another aspect of the present invention, by providing a tab which issized to fit within the center passage of a coil spring, one of theannular support plates can be omitted. In its place are disk shapedpressure plates for each coil spring which reduces weight. Each of thedisk plates includes a locking tab surface that maintains the disk plateand spring relative to the remaining annular plate.

Even yet another aspect of the present invention, there are an evennumber of locking assemblies around the circumference of the annularplates. One group of locking assemblies has the first tab extending fromthe first plate and the second group has the first tab extending fromthe second plate. By using two groups of locking assemblies, the tabs ofa plate alternate between a tab with the guide slot and a tab with thehook. The tabs may be integrally formed in the guide plates as inOrlowski. In the one embodiment, four locking assemblies are usedwherein the integral tabs at the twelve o'clock position and six o'clockposition have one construction and the tabs at the three o'clockposition and nine o'clock position have the opposite configuration. Bymerely indexing the plates 90°, identical plates can be used inconstructing the ring shaped spring device.

Yet a further aspect of the present invention relates to utilizingmolded tab components which incorporate one-way barbs or locking tabs tomaintain the plates relative to one another. In this respect, one of theannular plates includes a plurality of spaced receptacles correspondingto the position of the coil springs. The receptacles are sized so thatthe coil springs fit about the receptacle. The other annular ringincludes posts which also correspond to the position and number of coilsprings. The receptacle is shaped to receive the post and includesone-way or locking barbs such that once the post enters the receptacle,it can not be removed.

Another aspect of the present invention involves spring tabs to locatethe coil springs around the annular plates. These spring tabs are lancedfrom the edge of the annular plates and are bent downwardly atcircumferentially spaced locations around the plates. The tabs are bentdownwardly from a point generally at the midpoint of the plates, wherebythe coil springs are located by the tabs in or near the center of theannular plates. This configuration allows the spring tabs to be producedby a simple punch press operation that first lances and then bends thetabs relative to the plate. This operation is much simpler than thecomplex bending operation required in Orlowski.

An object of the present invention is the provision of an improvedring-shaped spring device having two annular plates used to capture andlocate circumferentially spaced coil springs, wherein the spring deviceguides the movement of the annular plates as the springs are compressedand/or released and solving the deficiencies of Orlowski U.S. Pat. No.5,306,086.

Another object of the present invention is the provision of a springdevice which utilizes locking assemblies that fit within the centerpassage of one of the coil springs so as to maximize the number ofsprings that can be utilized and balancing the spring action around theassembly.

Yet a further object of the present invention is the provision of aring-shaped spring device wherein spaced annular plates are heldtogether by lock assemblies having members that limit the movementbetween the plates to a generally vertical sliding movement as theplates move vertically to compress and/or release the coil springs, sothe plates are fixed in a circumferential direction.

Even yet a further object of the present invention is the provision ofreplacing one annular ring with independent disk shaped pressure platescorresponding to each coil spring.

Another aspect of the present invention is the provision of utilizingmolded components having one-way or locking barbs that can be easilysnap-fitted together.

Even yet another object of the present invention is the provision ofeliminating one annular ring by utilizing coil spring which caninterengage with the other annular ring.

These and other objects and advantages will become apparent from thefollowing description taken together with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a top plan view of the ring shaped spring device constructedin accordance with an embodiment of the present invention;

FIG. 2 is an enlarged cross-sectional view taken generally along line2—2 of FIG. 1;

FIG. 2A is an enlarged cross-sectional view similar to FIG. 2 showingthe top hook tab is formed from material near the inner rim of topannular ring;

FIG. 3 is a cross-sectional view taken generally along line 3—3 of FIG.2;

FIG. 3A is a cross-sectional view taken generally along line 3A—3A ofFIG. 2A;

FIG. 4 is an enlarged exploded partial view of the spring device shownin FIG. 1;

FIG. 5 is an enlarged cross-sectional view of another embodiment of aring shaped spring device according to the present invention;

FIG. 6 is a cross-sectional view taken generally along line 6—6 of FIG.5;

FIG. 7 is a top plan view showing another embodiment of a ring shapedspring device according to the present invention;

FIG. 8 is an enlarged cross-sectional view taken generally along line8—8 of FIG. 7;

FIG. 9 is an enlarged cross-sectional view taken generally along line9—9 of FIG. 7;

FIG. 10 is an enlarged exploded partial perspective view of thering-shaped device shown in FIG. 7;

FIG. 11 is a top plan view of yet another embodiment of a ring shapedspring device according to the present invention;

FIG. 12 is an enlarged cross-sectional view taken generally along line12—12 of FIG. 11;

FIG. 13 is an enlarged cross-sectional view taken generally along line13—13 of FIG. 11;

FIG. 14 is an enlarged cross-sectional view taken generally along line14—14 of FIG. 11;

FIG. 15 is an enlarged cross-sectional view taken generally along line15—15 of FIG. 11;

FIG. 16 is an enlarged exploded partial perspective view of the springdevice shown in FIG. 11;

FIG. 17 is a top plan view of even yet another embodiment of a springshaped spring device according to the present invention;

FIG. 18 is an enlarge cross-sectional view taken generally along line18—18 of FIG. 17;

FIG. 19 is a cross-sectional view taken generally along line 19—19 ofFIG. 18;

FIG. 20 is an exploded partial perspective view of the spring deviceshown in FIG. 17;

FIG. 21 is a top plan view of still yet a further embodiment of a ringshaped spring device according to the present invention;

FIG. 22 is an enlarged cross-sectional view taken generally along line22—22 of FIG. 21; and,

FIG. 23 is an exploded partial perspective view of the spring deviceshown in FIG. 21.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings, wherein the showings are for the purposeof illustrating preferred embodiments of the invention only and not forthe purpose of limiting same, FIGS. 1, 2, 3 and 4 show a ring shapedspring device 8 having annular spaced-apart plates 10, 12 with outerrims 14, 16, respectively, and inner edges 15, 17. Plates 10, 12 arecoaxial to axis 18 and include spring tabs 20 of plate 10 and springtabs 22 of plate 12. The tabs, sometimes called “elements”, are lancedfrom a center portion of its respective plate and are bent to locate atcircumferentially spaced positions a number of coil springs 30. Thespring tabs 20, 22 have spaced distal edges 20 a, 22 a facing oneanother and have a length such that there is a gap between edges 20 a,22 a when device 8 as a whole is in a free state. Edges 20 a, 22 aengage one another to limit the vertical movement of plates 10, 12toward one another. The widths W of the spring tabs are just slightlysmaller than the diameters of passages 32 of springs 30. Any number oftabs and springs can be circumferentially spaced around plates 10, 12.In a preferred embodiment, twenty-four springs are employed and areequally spaced around plates 10, 12. The tabs or elements extend throughthe springs so there is no circumferential gap in the circular array ofcoil springs.

Four lock assemblies 40, 42,44 and 46 are utilized to maintain plates10, 12 relative to one another and arc positioned within center passages32A, 32B, 32C and 32D of coil springs 30A, 30B, 30C and 30Drespectively. By positioning the lock assemblies within the coilsprings, four additional coil springs can be utilized thereby increasingthe possible overall spring force of spring device 8 without changingthe design of coil springs 30. All lock assemblies 40, 42, 44 and 46 areessentially the same, however, the orientation of the assemblies isalternated one lock assembly to the next which allows plates 10, 12 tobe identical. In this respect, while each lock assembly is structurallythe same, lock assemblies 40,44 are oriented in one direction and lockassemblies 42, 46 are oriented in the opposite direction. Plates 10, 12are merely positioned facing each other and are rotated 90° relative toone another about axis 18 to properly align lock assemblies 40, 42,44and 46. The advantage of this concept is that by using identical plates,manufacturing and inventory costs can be reduced.

Since all lock assemblies 40, 42, 44 and 46 are structurally the same,only lock assembly 40 will be described in detail and this descriptionapplies to the other lock assemblies 42, 44 and 46. However, as statedabove, assemblies 42, 46 are oriented differently. Lock assembly 40includes hook tabs 50, 52 which are provided on the opposite plates 10,12. Tabs 50, 52 are created by forming a lanced portion of plates 10,12, respectively, wherein tabes 50, 52 are still attached to plates 10,12, at bases edges 54,56 respectively. Turning to tab 50, it is lancedfrom an outer portion of plate 10 such that there is a gap in plate 10from base edge 54 which extends radially outwardly to rim 14. Tab 50 isbent at base edge 54 at a 90 degree angle from plate 10 toward plate 12and includes a base portion 66, an extension 68 and a distal end 58. Tab50 further includes a hook 62 on distal end 58 which is opened towardouter rim 14. Tab 52 is lanced from an inner portion of plate 12 suchthat there is a gap in ring 12 from base edge 56 which extends radiallyinwardly to edge 17. Tab 52 is bent at base edge 56 at a 90 degree anglefrom plate 12 towards plate 10 and includes base portion 70, anextension 72 and a distal end 60. Tab 52 further includes a hook 64 ondistal end 60 which is opened toward inner edge 17. When plates 10, 12are move vertically toward one another, hooks 62, 64 pass over eachother and then prevent the plates 10, 12 from being separatedvertically. As a result, plates 10, 12 can move vertically relative toone another, however, hooks 62, 64 prevent separation of the plates. Thelength of tabs 50, 52 determine the free-state height of device 8 as awhole and maintain the springs in a prestressed condition. In thisrespect coil springs 30 have a free-state spring height which isdifferent than the overall free-state height of device 8. The free-statespring height is achieved when coil springs 30 are unstressed andallowed to extend to a maximum spring height (not shown). The gapbetween plates 10, 12 is less than the free-state height for coilsprings 30 when hooks 62, 64 are interengaging with one another.Accordingly, springs 30 are exerting a force against plates 10, 12 evenwhen the overall spring device 8 is in its unstressed or free-statecondition. When an external force is applied to spring device 8, plates10, 12 move vertically downwardly toward one another and hooks 62, 64disengage. As discussed above, the downward vertical motion is limitedby edges 20 a, 22 a of spring tabs 20, 22 respectively.

In the following discussions concerning other embodiments, thecomponents of the spring device which remain the same, as discussedabove, will include the same reference numbers as above.

Referring to FIGS. 2A and 3A, Lock assembly 40 a is shown which worksthe same was way as lock assembly 40 except it includes hook tabs 52 and50 a. While tab 52 is the same as described above, tab 50 a is lancedfrom an inner portion of plate l0 a such that there is a gap in ring 10a from base edge 54 a which extends radially inwardly to edge 15. Tab 50a is bent at base at a 90 degree angle from plate 10 a toward plate 12.Tab 50 a is bent at base edge 54 a and includes a distal end 58 a with ahook 62 a which is opened toward outer rim 14 just like hook 62. Theonly difference being that tab 50 a is formed from an inner portion ofplate 10 a while tab 50 is formed from the outer portion. In similarfashion as assembly 40, when plates 10 a, 12 are move vertically towardone another, hooks 62 a, 64 pass over each other and then prevent theplates 10 a, 12 from being separated vertically.

Referring to FIGS. 5 and 6, a ring shaped spring device 100 is shownwhich is essentially the same as device 8 above except for amodification to the locking assemblies. More particularly, spring device100 includes annular spaced-apart plates 10, 102 with outer rims 14,104, respectively. Plates 10, 102 are coaxial to axis 18 and includespring tabs 20 (not shown) of plate 10 and spring tabs 22 (not shown) ofplate 102 which are configured the same as above and therefore will notbe discussed in detail. Any number of tabs and springs can becircumferentially spaced around plates 10, 102. In a preferredembodiment, twenty-four springs are employed and are equally spacedaround plates 10, 102.

Four lock assemblies 110, 112, 114 and 116 (only 110 is shown) areutilized to maintain plates 10, 102 relative to one another. As withdevice 8, assemblies 110, 112, 114 and 116 are structurally the sameexcept that they are oriented differently to allow plates 10, 102 to beidentical. Therefore only assembly 110 will be described in detail andthis description applies to the other lock assemblies 112, 114 and 116.Assembly 110 is positioned within center passage 32A of coil spring 30Aand includes hook tab 50, described above, and slot tab 122. Slot tab122 is formed from an inner portion of plate 102 and extends from a baseedge 124 to a distal end 126. Tab 122 extends at a 90° angle from plate102 toward plate 10 and has a maximum width 128 allowing it to fitwithin center passage 32A. Extending vertically in tab 122 is anelongated slot 130 having a width 132, a length 134 and a slot edge 136near distal end 126. Side edges 138, 140 are essentially parallel to oneanother and extend from either side of slot edge 136 toward plate 102.Tab hook 62 along with extension 68 have essentially a common widthwhich is slightly smaller than slot width 132 such that hook 62 canextend through slot 130. Accordingly, when plates 10, 102 are assembled,hook 62 first engages slot tab 122 and then enters slot 130. Once inslot 130, the engagement between hook 62 and slot edge 136 preventsseparation of plates 10, 102. In addition, the length of tab 50 and slot130 determine the free-state height of device 100 as a whole andmaintains springs 30 in a prestressed condition. Movement of plates 10and 102 relative to one another about axis 18 is controlled by theengagement between hook 62 and slot edges 138, 140. In this respect,hook 62 has hook edges 142, 144 and rotation is prevented in onedirection by the engagement between slot edge 138 and hook edge 142 andin the other direction by the engagement between hook edge and slot edge140.

Referring now to FIGS. 7-10, a ring shaped spring device 200 is shownwhich includes only one annular plate 202. Plate 202 includes an outerrim 204 and an inner edge 205. Plate 202 further includes spring tabs206 which are lanced from an inner portion of plate 202 wherein tabs 206are still attached to plate 202 at base edges 207. In this respect, tabs206 are formed by an inner portion of plate 202 such that there is a gapin plate 202 from base edge 207 which extends radially inwardly to edge205. Tabs 206 are bent at a 90 degree angle at base edge 207 from plate202. The widths W of the spring tabs are smaller than the diameters ofthe passages 208 of springs 210. Any number of tabs and springs can becircumferentially spaced around plate 202. In a preferred embodiment,twenty-four springs are employed and they are equally spaced aroundplate 202.

Each spring tab 206 includes a vertically extending slot 212 having atop edge 214, a bottom edge 216 and parallel side edges 218 and 220.Each spring 210, is made from a single wire 228 and includes a bottomedge 230 which rests on plate 202 and a top edge 232 spaced from bottomedge 230. Spring 210 further includes extension 234 which is acontinuation of wire 228 and which extends downwardly into centerpassage 208. At the end of extension 234 is a hook 238 shaped and sizedto enter slot 212. Spring 210 is assembled to plate 202 by urging spring210 over tab 206 and partially compressing spring 210 until hook 238enters slot 212. Once hook 238 enters slot 212 it maintains spring 210relative to plate 202 in a prestressed condition with spring bottom 230engaging plate 202. As spring 210 is compressed by the transmission,hook 238 rides in slot 212 between top and bottom edges 214, 216respectively.

Referring now to FIGS. 11-16, yet even another embodiment is shown.Shown is a ring shaped spring device 300 having annular spaced apartplates 302, 304 with outer rims 306, 308, and inner edges 307, 309,respectively. Device 300 includes spring tabs 310 for plate 302 andspring tabs 312 for plate 304 which are each lanced from an innerportion of plates 302, 304, respectively, wherein tabs 310 are attachedto plate 302 at bases edges 314 and tabs 312 are attached to plate 304at base edges 316. In this respect, tabs 310 are formed from an innerportion of the plates between base edges 314, 316 and inner edges 307,309 respectively. Tabs 310, 312 are bent at a 90 degree angle at baseedges 314, 316. The widths W of the spring tabs are smaller than thediameters of passages 32 of springs 30. Any number of tabs and springscan be circumferentially spaced around plates 302, 304. In a preferredembodiment, twenty-four springs are employed and are equally spacedaround plates 302, 304. Spring tabs 310, 312 have spaced distal edges317, 318 facing one another and have a length such that there is a gapbetween edges 317 and 318 when device 300 as a whole is in a free state.Edges 317, 318 engage one another to limit the vertical movement ofplates 302, 304 toward one another.

Four lock assemblies 320, 322, 324 and 326 are positioned about plates302, 304. While four such assemblies are shown, as with the otherembodiments, a different number of assemblies could be utilized. As withprevious embodiments, assemblies 320, 322, 324 and 326 are structurallythe same except that they could be oriented differently to allow plates302, 304 to be identical. Therefore only assembly 320 will be describedin detail and this description applies to the other lock assemblies 322,324 and 326. Referring with particular reference to FIGS. 14, 15 and 16,lock assembly 320 includes a hook tab 350 and a notch tab 352. Tabs 350,352 are created by forming a lanced portion of plates 302, 304,respectively, wherein tabes 350, 352 are still attached to plates 302,304 at bases edges 354, 356 respectively. Turning to tab 350, it islanced from an inner portion of plate 302 such that there is a gap inplate 302 from base edge 354 to inner edge 307. Tab 350 is bent at baseedge 354 ninety degrees from plate 302 toward plate 304 and includes abase portion 358, an extension 360 and a distal end 362. Extension 360has a width which is approximately half the width of base portion 358and further, extension 360 extends from one side of base portion 358thereby making hook tab 350 L-shaped. Tab 350 further includes a hook364 on distal end 362 which is opened toward inner edge 307. Tab 352 islanced from an inner portion of plate 304 such that there is a gap inring 304 from base edge 356 to edge 309. Tab 352 is bent at base edge356 ninety degrees from plate 304 toward plate 302 and is essentiallyC-shaped having outer side edges 366, 368 which extend from plate 304towards distal end 370 of tab 352. Side edge 368 includes a notch 372having parallel notch edges 374, 376 that are joined by vertical notchedge 378. The length of notch edges 374, 376 corresponds with the widthof hook 364. With particular reference to FIG. 15, by utilizing L-shapedhook tab 350 and C-shaped notch tab 352, assembly 320 can fit withinspring cavity 32 and can be assembled without forcing hook 364 to deformin order to pass over its engagement point on notch tab 352. In thisrespect, while within cavity 32, hook 364 can be manipulated to passnext to edge 368 and then to be positioned within notch 372. As hook 364is being manipulated into notch 372, spring 30 is partially compressed.Once in notch 372, spring 30 forces plates 302 and 304 away from oneanother until hook 364 engages edge 374.

Referring now to FIGS. 17-20, a ring shaped spring device 400 is shownwhich includes annular spaced apart plates 402, 404 with outer rims 406,408 and inner edges 407, 409, respectively. Spring device 400 is shownto include twenty-four lock assemblies 410, however, it should be notedthat less than twenty-four lock assemblies could be used and less thantwenty-four coil springs 30 could be used. However, it is preferred thatall twenty-four springs 30 are used in connection with twenty-four lockassemblies 410. Lock assemblies 410 are all identical and each includesa receptacle 412 and a post 414. Receptacle 412 is cylindrical with abase end 420 secured to plate 404 and which extends toward plate 402.Receptacle 412 has a distal end 422 spaced from end 420 that includes anopening 424 to an inner portion 428. Receptacle 412 further includesseveral barbs 426 that extend downwardly into inner portion 428. Post414 includes a base 430 connected to plate 402 and extends toward plate404. In addition, post 414 includes a tapered lead 432 which is shapedto urge barbs 426 outwardly and allow a portion of post 414 to enterinner portion 428. Post 414 further include locking groove 434 having acylindrical portion 436 and a frustum conical portion 438 adjacent tocylindrical portion 436. As a result, once tapered lead 432 urges barbs426 outwardly and allows the end of post 414 to enter inner portion 428,barbs 426 spring into locking groove 434 thereby retaining post 414relative to receptacle 412. Cylindrical portion 436 provides for thecompression of spring 30 by allowing post 414 to move downwardly intoinner portion 428. However, barbs 426 do not allow post 414 completelypull out of inner portion 428. Furthermore, the vertical dimensions ofpost 414 and receptacle 412 are such that when barbs 426 engage edge440, springs 30 remain in a prestressed condition. In addition, theengagement between the post and the receptacle prevent rotationalmovement of plate 402 relative to plate 404 about axis 18.

Referring to FIGS. 21-23, a ring shaped spring device 500 is shown whichincludes only single annular plate 404 as described above. Spring device500 further includes twenty-four receptacles 412 which are the same asdescribed above with respect to spring device 400. However, device 500includes twenty four independent post assemblies 508. While each postassembly 508 includes posts 414 as described above, each post assembly508 is joined to a post disk 510 that has a diameter greater than theouter diameter of springs 30. This results in each post assembly 508moving independent of one another. The functional relationship betweenpost 414 of assemblies 508 and receptacle 412 is also the same asdescribed above with respect to spring device 400 and therefore will notbe described in detail.

While considerable emphasis has been placed on the preferred embodimentsof the invention illustrated and described herein, it will beappreciated that other embodiments can be made and that many changes canbe made in the preferred embodiments without departing from theprinciples of the invention. Accordingly, it is to be distinctlyunderstood that the foregoing descriptive matter is to be interpretedmerely as illustrative of the invention and not as a limitation.

1. A spring device comprising at least one annular support platedefining a ring with a central ring axis; a plurality ofcircumferentially spaced, parallel oriented coil springs disposed on oneside of said at least one plate and having associated therewith afree-state height for said coil springs, said coil springs being coiledabout a spring axis which defines a spring center passage and having afirst end engaging said one side and a second end spaced from said firstend; and, a plurality of lock assemblies located at circumferentiallyspaced positions around said ring, each of said lock assemblies beingwithin one of said center passages, said plurality of lock assembliesmaintaining said engagement between said first end and said one side butpreventing said coil springs from reaching said free-state height.
 2. Aspring assembly, as defined in claim 1, wherein said locking assembliesare formed integrally of one of said at least one plate.
 3. A springdevice comprising a pair of spaced-apart first and second annularsupport plates defining a ring with a central ring axis; a plurality ofcircumferentially spaced, parallel oriented coil springs disposedbetween said annular plates and having associated therewith a free-stateheight for said coil springs, said coil springs being coiled about aspring axis which defines a spring center passage; and, a plurality oflock assemblies located at circumferentially spaced positions aroundsaid ring, each of said lock assemblies being within one of said centerpassages and including a first element extending from one of saidplates, a second element extending from said other of said plates, saidfirst and second elements interengaging to allow said plates to movetoward or away from each other to compress and/or release said coilsprings but preventing said coil springs from reaching said free-stateheight.
 4. A spring assembly, as defined in claim 3, wherein saidelements are formed integrally of said plate from which they extend. 5.A spring assembly, as defined in claim 3, wherein said first elementextends from said one plate toward a distal end facing the other of saidplates and said second element extends from said other plate toward saidone plate, said distal end including a hook, said second element havingparallel sides extending from said other plate, one of said parallelsides including a notch having opposing notch edges transverse to saidparallel sides, said hook extending into said notch such that saidplates can move toward and away from each other to compress and/orrelease said coil springs, said hook engaging one of said notch edges toprevent said coil springs from reaching said free-state height.
 6. Aspring assembly, as defined in claim 5, wherein said first and secondelements are formed integrally of said plate from which they extend. 7.A spring device comprising a pair of spaced-apart first and secondannular support plates defining a ring with a central ring axis; aplurality of circumferentially spaced, parallel oriented coil springsdisposed between said annular plates and having associated therewith afree-state height for said coil springs, said coil springs being coiledabout a spring axis which defines a spring center passage; and, aplurality of lock assemblies located at circumferentially spacedpositions around said ring, each of said lock assemblies being withinone of said center passages and including a first tab extending from oneof said plates toward a first distal end facing the other of saidplates, a second tab extending from said other of said plates toward asecond distal end facing said one of said plates, said first distal endbeing curved toward said axis to form an inwardly facing hook, saidsecond distal end being curved away from said axis to form an outwardlyfacing hook and facing said inward hook, said inward and outward hooksinterengaging to allow said plates to move toward or away from eachother to compress and/or release said coil springs but preventing saidcoil springs from reaching said free-state height.
 8. A spring assembly,as defined in claim 7, wherein said tabs are formed integrally of saidplate from which they extend.
 9. A spring device comprising a pair ofspaced-apart first and second annular support plates defining a ringwith a central axis; a plurality of circumferentially spaced, paralleloriented coil springs disposed between said annular plates and havingassociated therewith a free-state height for said coil springs, saidcoil spring being coiled about a spring axis which defines a springcenter passage; and, a plurality of lock assemblies located atcircumferentially spaced positions around said ring, each of said lockassemblies being within one of said center passages and including afirst tab extending from one of said plates toward a distal end facingthe other of said plates, a second tab extending from said other of saidplates toward said one of said plates, said distal end being curved toform a hook having a width and which faces said second tab, said secondtab having a locking slot with a given width greater than said hookwidth and extending in a direction perpendicular to said plates, saidhook extending through said slot to allow said plates move toward andaway from each other to compress and/or release said coil springs, saidhook engaging said slot to prevent said coil springs from reaching saidfree-state height.
 10. A spring assembly, as defined in claim 9, whereinsaid tabs are formed integrally of said plate from which they extend.11. A spring device comprising a pair of spaced-apart first and secondannular support plates defining a ring with a central ring axis; aplurality of circumferentially spaced, parallel oriented coil springsdisposed between said annular plates and having associated therewith afree-state height for said coil springs; and, a plurality of lockassemblies located at circumferentially spaced positions around saidring, each of said lock assemblies including a first tab extending fromone of said plates toward a distal end facing the other of said plates,a second tab extending from said other of said plates toward said one ofsaid plates, said distal end being curved to form a hook having a widthand which faces said second tab, said second tab having a locking slotwith a given width generally matching, but slightly larger than saidhook width and extending in a direction perpendicular to said plates andsaid hook extending through said slot to allow said plates to movetoward and away from each other to compress and/or release said coilsprings, said hook engaging said slot to prevent said coil springs fromreaching said free-state height, and to prevent relative rotationbetween said annular plates about said ring axis.
 12. A spring assembly,as defined in claim 11, wherein said tabs are formed integrally of saidplate from which they extend.